Process for the preparation of glyoxal sulphate



res sa er PROCESS FOR THE PREPARATION OF GLYOXAL SULPHATE Mclvin A. Perkins, Milwaukee, Wis, assig'nor to E. L-du Eont de Nemours & Company, Wilmington, Del, a corporation of Delaware No Drawing. Application November 10, 1933,

. Serial N0. 697,474

4 Claims; r01. zoo-99.12)

This invention relates to a new and improved understood that my i vention is not to be lim- 7 process for preparing glyoxal sulphate. ited thereby. The parts used are'by weight.

According to German Patent -No,.362,743 of 1.7 parts of mercurous sulphate are introduced 7 of 1922, glyoxal sulphate is prepared by slowly into 400 parts of 65% oleum contained in a glass, adding 65% oleum to tetrachlorethane contain enameled, or iron vessel, provided with tempera- I ing mercury sulphate in suspension. By followture recorder, inlet tube and small vent. (for exit ing the procedure of this Germanpatentfl have of fumes). The mixture'is gradually heated, with foundthat the yields obtained are only a small stirring; to 55 65" C., and 100 parts of tetra-, fraction of theory. Furthermore, great care must chlorethane are added duringthe course of about be exercised in adding the oleum due to the fact two hours. Since the oleum fumes strongly at 10 that the reaction does not start until a certain first, about 10% of i the .tetrachlorethane 1(10 amount of oleum has been added, and-when the parts) is addedduring the period of heating the reaction starts it tends to proceed violently and oleum-n'iercury sulphate mixture to 55. This reis difncult and oftimes impossible tocontrol, duces the fuming considerably. The remainder It is an object of my invention to provide a (96 parts) of the tetrachloretnane is then add- 5 process which will give glyoxal sulphate in high ed at,55 65, preferably at 60-65? C. After all yields, and one which may be readily controlled oi the tetrachlorethane has been added, the

and the hazards of the known process eliminated. charge is further heated and stirred for about I have found that by slowly adding tetrachlortwo hours at 55-65 C. The crystalline magma 2O ethane to strong oleum containing mercury sulis then cooled to 25, C. or below and filtered on chlorethane; yields of glyoxal sulphate increase to somewhat larger proportions of mercuric sul- 3r phate, and by warming the mass further until a porous stone filter (filtrose). The cake is reaction is complete, a comparatively high yield washed or slurred with. 100% sulphuric acid of glyoxal sinphate is obtained. The reaction (about 400 parts),filtered if necessary, and finally proceeds smoothly and in an easily controllable drowned in ioewater, filtered, washed with icemanner. By using the materials and conditions water and dried, preierably'below 80 0. Pure of German Patent No. 362,743, and reversing the white crystals ofglyoxal sulphate are thus ob- 7 order of adding the materials so that the tetratained, of excellent purity andinyields of 70-73%, 'chlorethane is added to the oleum solution of based on tetrachlorethane.

mercury sulphate, the yields are increased well The reaction maybe carried out equally well 39 over 100% of that heretofore obtained. in glass or iron vessels, and oleum of the conj Still further gains are realized by regulating centrations above described may be used, althe time of reaction, temperature; proportion of though oleum of from about 50 to 65% is precatalyst and, particularly, ratio of tetrachlorferred. In the example, 1.7 to 1'7 parts of mer-,

ethane to oleuni. Based on one part or" tetracurous sulphate can be used, and is equivalent progressively as the proportion of 65% oleum is phate, which may be substituted therefon, .Other increased from 2.4 to 6 parts, although the yield catalysts, such as copper sulphate, have also been increase is relatively small at more than l parts found to be suitable.

of oleum. Temperatures of C. to 66 C. have What I claim is:

40 been found to be operative, although the upper 1. In the process for preparing glyoxal sulphate limits of temperature give highest yields. Maxiwhich comprises reacting tetrachlorethane and mum yields are obtained in an approximately oleum in the presence of a catalystfor the reac-' e-hour reaction period, both shorter and longer tion, the step which comprises slowly adding reaction periods resulting in loss of yield, although tetrachlorethane to oleurn of over 25%.

the reaction is not so sensitive to this as to other 2. In the process for preparing glyoxal sulphate variables, and from 1 to 5 hours have been which comprises reacting tetrachlorethane and found l10 give good results. AS to theproportion oleum in the presence of a catalyst for therea'cof catalyst, improvement is obtained by reducing mm, the step which comprises slowly adding the amount to one-hair" that used in German tetrachlorethane to oleum'of to 50 Patent No. 362,743. W e prefer to use'65% oleum, 3. In the process for preparing glyoxal sulphate 50 although acids or" materially lower S03 content which comprises reacting tetrachlorethane and can also be used, the lower limit being about 25% oleum in the presence of a catalyst for the reacfree anhydride. 7 tion, the steps which comprise slowly adding The following exam le is given to illustrate the tetrachlorethane to oleum of 50 to 65% and bring- 5 preferred mode of operation, although it is to be ing the temperature of the reaction to 55,-65 C. I

4. in the preparation steps which comprise of glyoxal sulphat 'gseases.

e the slowly adding about 10 f of tetrachloreth 55 to about 65 ane 0 the mass at from about the glyoxal sulphate from the reaction mass.

NHHJHN'A.PERKINS. 

